Appears In: BoA
Also Called: Donut Age, Impossible Age (credit: J'ohn)
The Torus Age was Catherine's first Age, written under Gehn's tutelage. She showed it to Atrus when he arrived on Riven. He described it as impossible, but the Age clearly was able to exist, because the Book worked, and the two of them explored the Age.
The Age itself is, as its name implies, shaped like a giant ring, with most of the planet's mass on the outer end of the rim. This created a ring-shaped gravitational field as well. The planet was aligned with the sun such that there was a light side and a dark side. On this dark side there were strange, firefly-like creatures which were able to change their shape to fit through Atrus' legs as if they were a soap bubble. In the center of the dark side of the Age was an enormous fountain of water, which thundered straight up into the black of the sky, illuminated from below by the glow of the sun from the light side of the planet.
The source of this strange column of water can be found on the light side of the planet. Here, in the center, a massive lake feeds the waterfall through a central hole in the planet. The water falls through the hole, out the other side, and arcs around to form clouds in the atmosphere on the light side, which then create rain, thus re-feeding the lake.
One of the more remarkable things found on the light side of the planet are fields of small blue flowers, which could also be found at the site of Atrus' mother's grave in the Cleft. The fact that Catherine knew about them took Atrus aback at first, but he seemed to put the matter aside and leave it an unknown. As it is later revealed that Catherine had been working with Atrus' grandmother at the time in an effort to trap Gehn, it is possible that Catherine learned about the flowers and their significance through her.